JPH0639584B2 - Adhesive tape - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive tape, and more particularly to an adhesive tape having good workability.

"Prior Art" Conventionally, to give the co-polymer and diorganopolysiloxane gum consisting of SiO ₂ units and (CH _{3) 3} SiO _0.5 units to a support tape, such as polyimide and an organic fluoropolymer condensed A pressure-sensitive silicone adhesive tape formed by applying a silicone adhesive is known. However, the pressure-sensitive adhesive tape is poor in anchoring force of the pressure-sensitive adhesive layer to the support tape, and the adhesiveness is deteriorated due to migration of components in the pressure-sensitive adhesive layer to the pressure-sensitive surface over time or in a high temperature environment, and At the time of cutting, even if the support tape is cut, the pressure-sensitive adhesive layer is not cut, resulting in poor cutting and poor workability.

Therefore, in order to solve these drawbacks, a method of chemically treating or electrically treating the surface of the support tape in advance has been taken, but it is still not satisfactory.

Further, in JP-B-54-44017, a cured layer of a primer composition comprising a hydroxyl group-terminated diorganopolysiloxane, an organohydrogenpolysiloxane and an organic carboxylic acid tin salt is provided, and a silicone adhesive layer is provided thereon. A method has been proposed, but the cutting property is not satisfactory even with this method.

Further, in Japanese Patent Publication No. 60-11950, the above-mentioned drawbacks are improved by providing a cured layer of a primer composition comprising a vinyl group-containing diorganopolysiloxane, an organohydrogenpolysiloxane and a platinum catalyst.
Since the primer composition has a short pot life and a high curing temperature, it is not suitable for an adhesive tape having a support such as polyester.

In addition, although a method of applying a carbon functional silane-based primer to the surface of the support treated by the above-mentioned method is also proposed, not only sufficient improvement in anchoring property has not been achieved, but low temperature / No improvement has been made to improve productivity and economic efficiency such as short-time curing.

<< Problems to be Solved by the Invention >> As a result of intensive investigations by the present inventors to solve the above drawbacks,
Α, ω-dihydroxydiorganopolysiloxane, organohydrogenpolysiloxane as a primer,
When a composition comprising a hydrolyzable silyl group-containing vinyl-based and / or acrylic-based copolymer and an organic carboxylic acid metal salt is used under certain conditions, it is possible to obtain an adhesive tape having good cutability and good workability. The present invention has been achieved by finding that the manufacturing can be performed with high production efficiency.

Therefore, an object of the present invention is to provide an adhesive tape having high workability and high production efficiency.

<< Means for Solving the Problems >> The above objects of the present invention are (a) general formula (B) An organohydrogenpolysiloxane having at least three hydrogen atoms bonded to a silicon atom in one molecule and having a substituted or unsubstituted monovalent hydrocarbon group as an organic group. The present invention is achieved by an adhesive tape characterized in that an adhesive layer is provided via a cured layer composed of (c) a hydrolyzable silyl group-containing vinyl-based and / or acrylic-based copolymer and (d) an organic carboxylic acid metal salt. It was

The diorganopolysiloxane represented by the above general formula (hereinafter referred to as the component (a)) enhances the cohesive force and the adhesive force of the treated layer as the undercoating agent, and R in the formula is a substituted or unsubstituted monovalent compound. It represents a hydrocarbon group, and n is an integer of 30 or more.

Examples of the organic group represented by R include alkyl groups such as methyl group and ethyl group, substituted alkyl groups such as chloropropyl group and tolfluoropropyl group, alkenyl groups such as vinyl group and allyl group, and aryl groups such as phenyl group. Can be illustrated, but from the industrial viewpoint, a methyl group or a phenyl group is particularly preferable.

The diorganopolysiloxane has a degree of polymerization of 30 or more, preferably 300 or more.

A diorganopolysiloxane having a degree of polymerization of 30 or less has low viscosity and cohesive force.

The organohydrogenpolysiloxane used in the present invention (hereinafter referred to as (b) component) crosslinks the diorganopolysiloxane of (a) component, and
It can be appropriately selected from those containing at least three hydrogen atoms bonded to silicon atoms, and may be cotton-like, branched, or cyclic. Specific examples of the substituted or unsubstituted monovalent hydrocarbon group include those similar to the case of the diorganopolysiloxane.

Examples of the organohydrogenpolysiloxane include: Alternatively, (CH ₃ ) ₃ SiO _0.5 unit, (CH ₃ ) ₂ HSiO _0.5 unit, (CH ₃ ) ₃ Si
O unit, (C ₆ H ₅ ) ₂ SiO unit, CH ₃ SiO _1.5 unit,
Examples include hydrogen-containing copolymers having at least two types of units of C ₆ H ₅ SiO _1.5 units and SiO ₂ units.

However, a to d represent an integer of 3 or more.

The blending amount of the organohydrogenpolysiloxane of the component (b) is 1 with respect to 100 parts by weight of the component (a).
It is preferably from 50 to 50 parts by weight, and particularly preferably from 5 to 20 parts by weight. When the blending amount is 1 part by weight or less, the crosslinking density is low and the workability during tape production is deteriorated.
If it is used in an amount of 50 parts by weight or more, the flexibility is poor and the commercial value as an adhesive tape is lost.

In the present invention, various organopolysiloxanes can be contained in addition to the components (a) and (b) described above,
To the extent that transparency is not impaired, a copolymer consisting of (CH ₃ ) ₃ SiO _0.5 units and SiO ₂ units, a chain-like diorganopolysiloxane whose terminal group is an alkoxy group or an organic group, etc. are appropriately added. May be.

Next, the hydrolyzable silyl group-containing vinyl-based and / or acrylic-based copolymer (hereinafter referred to as (C) component) used in the present invention will be described.

This component improves the anchoring force of the adhesive layer to the support, and thereby improves the adhesiveness and cuttability.

In the present invention, it is preferable to use, as the component (c), a monomer obtained by copolymerizing a monomer having both an alkoxysilyl group and a radical polymerizable unsaturated group with another radical polymerizable monomer.

Examples of the monomer having both the alkoxysilyl group and the radical polymerizable unsaturated group include, for example, And the like, and particularly CH ₂ = CHSi (OCH ₃ ) ₃ , CH ₂ = CHSi (OC ₂ H ₅ ) ₃ , CH ₂ = CHSi (OCH ₂ CH ₂ OCH ₃ ) ₃ , It is preferable from an industrial viewpoint.

Other radically polymerizable monomers copolymerized with the above monomers include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic. 2-hydroxyethyl acid,
Examples include 2-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, N-methylrollacrylamide, vinyl acetate and the like.

The copolymerization of the above radical polymerizable monomer and the above-mentioned hydrolyzable silyl group-containing monomer can be carried out using a radical initiator such as azoisobutylnitrile or benzoylperoxide. In this case, the content of the hydrolyzable silyl group-containing monomer is preferably 5 to 50% by weight, and if the content is outside this range, the adhesiveness and cuttability cannot be improved.

The amount of the component (c) is solid, and is preferably 0.1 to 10 parts by weight, and particularly preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the component (a). If it is less than 0.1 parts by weight, the adhesive strength will be weak, and if it is more than 10 parts by weight, the flexibility will be poor.

The organic carboxylic acid metal salt used in the present invention (hereinafter referred to as component (d)) is a curing catalyst for components (a) to (c), and examples thereof include dibutyltin diacetate, dibutyltin dioctoate, and dibutyltin dilaurate. , Tin octoate, tin naphthate, tin oleate, lead octoate, iron octoate, zinc octoate, and the like. Among these, tin salts such as dibutyltin diacetate and dibutyltin dioctoate are preferable. From the viewpoint of curability, pot life, etc., the amount of the compounded is preferably 0.5 to 10 parts by weight per 100 parts by weight of the component (a).

When actually using the composition comprising the above components (a) to (d) as a primer, for example, benzene, toluene, xylene, petroleum ether, hexane in order to coat the support tape uniformly with good workability. Organic solvents such as trichloroethylene and tetrachloroethylene are used, and among these, toluene is particularly preferable. In order to make the anchoring force to the support of the adhesive layer sufficient,
It is necessary to adjust the dry film thickness of the primer layer to 1-2 μm, and in order to obtain this film thickness, the nonvolatile content of the primer coating solution is preferably 5 to 20% by weight.

The primer composition applied to the support is 60 to 100.
A cured film is reached at a low temperature of 30 to 90 seconds at a temperature of short time.

Examples of the support used for the pressure-sensitive adhesive tape of the present invention include polyimide, polyamide-imide, polyethylene terephthalate, organic fluoropolymer, metal foil, and the like, and particularly, polyethylene terephthalate whose surface is corona-discharge treated is most suitable. . The pressure-sensitive adhesive applied to the method of the present invention can be appropriately selected from conventionally known ones such as silicone-based or acrylic-based, but heat resistance,
A silicone-based pressure-sensitive adhesive having good durability and cold resistance is suitable.

<< Curing of the Invention >> As described in detail above, the pressure-sensitive adhesive tape of the present invention has a primer layer which is cured at a low temperature and in a short time between the support and the pressure-sensitive adhesive layer and has a good anchoring property, and thus has a good cut property. It has excellent workability, adhesiveness and production efficiency.

<< Examples >> The present invention will be described in more detail with reference to Examples below, but the present invention is not limited thereto.

All "parts" in the examples represent parts by weight.

Example 1. To 50 parts of toluene, a mixture of 34 parts of methyl methacrylate, 9 parts of 3-methacryloxypropyltrimethoxysilane, 7 parts of glycidyl methacrylate, 2 parts of ethyl acrylate, 2 parts of vinyl acetate and 1 part of azobisisobutyronitrile was added.
0 to 100 ° C., dropping in 3 hours, and 2 hours at 100 ° C. after finishing the dropping.
After aging for a time, 996 g of toluene was further added to obtain an acrylic copolymer solution having a nonvolatile content of 5.0%.

Next, 2 parts of the resulting acrylic copolymer solution, 10 parts of a hydroxydimethylpolysiloxane raw rubber having a viscosity of 350 poise of a 30% toluene solution and hydroxydimethyl at both ends, an average composition formula A mixture of 1 part of methyl hydrogen polysiloxane, 1 part of dibutyltin diacetate and 86 parts of toluene was subjected to corona discharge treatment on a polyethylene terephthalate film having a thickness of 0.025 mm and a width of 25 mm to give a dry film thickness of 1 μm. After coating and drying at 80 ° C for 30 seconds, a commercially available silicone adhesive (trade name: KR, manufactured by Shin-Etsu Chemical Co., Ltd.)
-120) A mixture of 100 parts, benzoyl peroxide 1.2 parts and toluene 50 parts was applied so that the dry film thickness would be 45 μm, heated at 80 ° C. for 20 minutes, and further heated at 150 ° C. for 5 minutes. A cured adhesive tape was obtained.

About the obtained adhesive tape, ball tack, adhesive strength,
The initial physical properties of cohesive strength and cutability are measured, and the same measurement is performed for 7 days after being left in an atmosphere of 50 ° C and 50% relative humidity and for 30 days after being left in an atmosphere of 70 ° C and 90% relative humidity. The deterioration was evaluated. In addition, as an index for deterioration evaluation, a phenomenon of peeling of the glue was further added. The results are as shown in Table-1.

However, the measurement conditions of each data are as follows.

[Ball tack]

A steel ball (SUJ2 of JIS G4805) was rolled from an approach distance of 10 cm on a slope with an inclination angle of 30 °, and indicated by the maximum diameter (inch) of the steel ball that stops within the range of 10 cm of the adhesive layer (tilt type). Ball tack measurement method). The conditions at the time of measurement are 25 ± 2 ° C. and 65 ± 5% relative humidity.

〔Adhesive force〕

Stainless steel plate of SUS304CP (thickness 1.0mm, width 3
0 mm, length 160 mm), lightly stick the pressure-sensitive adhesive layer side of the test piece to the center of the test piece, and apply a roller (weight of 2,000 ± 50 g covered with a rubber layer of about 6 mm thickness) from above. The test piece was crimped back and forth once with a crimping speed of about 300 mm / min.

The pressure-bonded test piece is 25 ℃ ± 2 ℃, relative humidity is 65 ±
After being left in a 5% constant temperature and humidity chamber for 30 minutes or more, the play part was folded back to 180 ° and the peeling force when peeled off continuously at a speed of 300 mm / min was shown.

[Cohesive force]

A test piece with an area of length 20 mm and width 10 mm is attached to a stainless steel plate, and a load of 1 kg is suspended in the vertical direction.
The deviation distance is shown after standing for 30 minutes in an atmosphere of ° C and relative humidity of 65 ± 5%.

[Cutability]

When the back of the adhesive tape is cut by about 3 mm from the side edge with a cutter and both ends are pulled and ruptured, the one that can be cut cleanly and integrally with the support without the adhesive layer extending or peeling from the support Is indicated by x.

[Peeling off phenomenon]

If the adhesive tape is adhered to a thermosetting silicone rubber plate and heated under pressure (20 g / cm ² ) at 70 ° C. for 20 hours, the adhesive does not transfer to the silicone rubber plate.
Those that migrate are indicated by x.

Example 2. After forming a primer layer in exactly the same manner as in Example 1, 100 parts of a commercially available silicone adhesive (trade name: X-40-3004 manufactured by Shin-Etsu Chemical Co., Ltd.) on this, an isopropyl alcohol solution of chloroplatinic acid ( Platinum content 0.05%) 2
1 part at 130 ° C.
It was dried for a minute to form an adhesive layer having a thickness of 45 μm. The obtained adhesive tape was evaluated in exactly the same manner as in Example 1. The evaluation results are as shown in Table-1.

Comparative Example 1. An adhesive tape was produced in the same manner as in Example 1 except that the acrylic copolymer used in Example 1 was not added at all.

The obtained adhesive tape was evaluated in exactly the same manner as in Example 1 and the results are shown in Table 1.

Comparative example 2. An adhesive tape was produced in exactly the same manner as in Example 1 except that 1 part of 3-methacrylopropyltrimethoxysilane was added instead of the acrylic copolymer used in Example 1.

The obtained adhesive tape was evaluated in exactly the same manner as in Example 1 and the results are shown in Table 1.

The results in Table 1 demonstrate that the pressure-sensitive adhesive tape of the present invention has excellent cuttability and has extremely excellent performance without deterioration.

Claims (1)

[Claims] 1. A general formula (a) on a support. (In the formula, R represents a substituted or unsubstituted monovalent hydrocarbon group, and n is an integer of 30 or more), and (b) a silicon atom is bonded to one molecule. An organohydrogenpolysiloxane having at least three hydrogen atoms and having a substituted or unsubstituted monovalent hydrocarbon group as an organic group, (c) a hydrolyzable silyl group-containing vinyl-based and / or acrylic-based copolymer, and (D) An adhesive tape characterized in that an adhesive layer is provided via a cured layer composed of an organic carboxylic acid metal salt.